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Monday, July 09, 2007

More on sounding analysis post-NWS RRS

On Saturday morning Jon wrote:

"The emphasis on the AFD and SPC forecasts, however, was whether coverage of the *severe* potential would be greater on Fri compared to Thu. Sure, it was more convectively active on Friday over Thursday. But, it is tough to say, at this point, on the coverage of severe thunderstorms based on no mention of such in media, print or LSRs from Friday. Have you seen any bonified severe reports from Friday?"

Actually, while there was lots of severe storm verbiage in the FD discussion the bottom line, as I interpreted it, had to do with general coverage of storms and POPs, which were left at previous levels. On Friday storms formed early; rained and anviled out by late afternoon; and there were no severe storm events, even though coverage of storms was greater. This often happens in the Tucson area, but it was not clear to me from the morning sounding that Friday was going to be an early storm day. Which leads to the issue of importance, as Jon stated:

"I agree--sounding assessment is tricky with the known problems. Thank goodness for PWAT sounders across the region."

I think that "tricky" may be an understatement. Consider this morning for example: The TWC sounding indicates IPW of 41mm with CAPE of well over 1000. These are quite high values for here and may (?) indicate much more storm potential today vs yesterday. The dilemma is that it appears that IPW is 5 to 6 mm too high wrt GPS IPW. The question is how does one know how to modify the "wet" Sippican data this morning? Where exactly is the phantom moisture that needs to be subjectively removed? How will this wet sounding affect the morning model runs?

Last evening the situation was just the opposite. The high resolution WRF model forecast indicated moderate CAPE at TWC at 0000 UTC, but topped by a layer of considerable CIN. However, the TWC sounding for that time indicated no CAPE whatsoever - but comparison of the IPWs indicated that last evening's Sippican data were about 7 mm too dry. Again the dilemma is: how do we know what the structure of the real atmosphere was?

I guess that I must admit that I am puzzled as to why there is so little reaction by any or all who are in atmospheric research and/or weather forecasting who use upper-air data or derived products. As for me, I am very angry and frustrated by the damage that's been done by the RRS program to the quality of the US upper-air sounding data!